Major League Baseball is poised to enter a new era of officiating with the implementation of the Automated Ball-Strike (ABS) Challenge System beginning in the 2026 season. This groundbreaking system will allow players to challenge the ball and strike calls made by human umpires, ushering in a blend of tradition, and technology.

How the ABS Challenge System Works

The ABS Challenge System doesn’t replace human umpires entirely. Instead, it provides a mechanism for review. Human umpires will continue to call balls and strikes, but teams will have the opportunity to challenge those calls. Each team will receive two challenges per game, with an additional challenge awarded in extra innings. If a challenge is successful, the team retains the challenge.

Only the batter, pitcher, or catcher can initiate a challenge by tapping their helmet or cap. Challenges must be made within two seconds of the pitch, and the result – a graphic displaying the pitch location and strike zone – will be shown on the scoreboard and broadcast feed. The umpire will then announce the corrected count.

“I commend the Joint Competition Committee for striking the right balance of preserving the integral role of the umpire in the game with the ability to correct a missed call in a high-leverage situation, all while preserving the pace and rhythm of the game.”

Commissioner Rob Manfred

The Technology Behind the System

The ABS system utilizes advanced camera and pose-tracking technology to create an individualized strike zone for each batter. This zone is determined by the batter’s height, measured without shoes. The system employs a network of cameras to track each pitch and determine whether it crosses home plate within the defined strike zone.

The strike zone itself is a rectangle, mirroring the dimensions outlined in the official rule book. It spans 17 inches in width and its height is determined by 53.5% of a player’s height at the top and 27% at the bottom.

The data is transmitted over a 5G network from T-Mobile’s Advanced Network Solutions and displayed nearly instantaneously.

Testing and Implementation

The ABS system has undergone extensive testing in the minor leagues since 2019, including trials at Triple-A since 2022, during MLB spring training, and at the 2025 All-Star Game. Teams won approximately 52.2% of their challenges during spring training last year, succeeding on 617 of 1,182 appeals.

The system’s debut will occur on Opening Night when the Giants host the Yankees, broadcast live on Netflix.

FAQ

What is the ABS Challenge System?

It’s a system that allows players to challenge ball and strike calls made by human umpires using automated technology.

Who can challenge a call?

Only the batter, pitcher, or catcher can initiate a challenge.

How many challenges does each team get?

Each team gets two challenges per game, with an additional challenge in extra innings.